During a charging process of a rechargeable battery, for example a traction battery for a vehicle having an electric drive, in the event of polarity reversal, a short circuit and damage to the battery or to the charging device can occur.
US 2005/0110467 A1, which is incorporated by reference herein, shows a charging device for a motor vehicle that has polarity detection means and overcurrent protection means. Depending on the polarity, the battery that is to be charged is connected to a direct current source by means of a bridge circuit with the correct polarity.
US 2015/0137740 A1, which is incorporated by reference herein, shows a mobile charging system having a polarity-reversal protection circuit, which checks the voltage at the battery by means of a comparator and, in the event of polarity reversal, closes a relay in order to activate a red light.
US 2016/0049819 A1, which is incorporated by reference herein, shows a battery charging device having means for checking for polarity reversal, wherein, in the event of polarity reversal, a warning signal is emitted.
Solutions are known in which a fuse and a diode having a flow direction from the negative branch to the positive branch are provided in the charging apparatus. In the case of polarity reversal, a large current flows via the diode and the fuse and the fuse breaks or blows. The power loss produced by the electrical resistance of the fuse during normal operation is disadvantageous.